1. Field of the Invention
The present invention relates to a field emission RF (Radio Frequency) amplifier, and more particularly, to a RF amplifier in which a field emission device carries out amplification.
2. Description of the Related Art
An RF amplifier receives a RF signal through an RF input terminal in the state that a predetermined DC bias voltage is supplied, and amplifies an amplitude of the RF signal to an RF output terminal. For such an RF amplification, the RF amplifier includes an RF amplification unit located between the RF input terminal and the RF output terminal.
A transistor can be the RF amplifier. However, since the transistor uses solid silicon, the transistor has poor electron mobility. Accordingly, a vacuum tube allowing electron transfer in a vacuum state can be substituted for the transistor, however, a problem exists that a conventional vacuum tube is too large in volume.
Studies for using a field emission device as the amplification unit in a vacuum panel are currently underway. An example of performing RF amplification using a silicon field emitter array is disclosed in “Silicon Field Emitter Arrays with Low Capacitance and Improved Transconductance for Microwave Amplifier Applications”, by D. Palmer, et al., J.Vac.Sci, Techno.B 13(2), Mar/Apr 1995, pp. 576–579.
However, since the FEA (Field Emission Array) structure used for RF amplification uses a gate insulating layer with 4 μm thickness consisting of silicon oxide, it is difficult to match standard input/output resistance of 50Ω of an RF device due to the increase of capacitance between the gate and the cathode. Also, such an increase of capacitance reduces an output current, thus deteriorating an amplification effect of an RF signal.